How to Apply HydroFix? Step-by-Step Application Guide

What Is HydroFix and Why Is It Used?

HydroFix is a silane/siloxane-based chemical injection liquid developed by Dryvatec. It is injected into the wall to create a chemical damp barrier (DPC - Damp Proof Course) in order to solve the rising damp problem. One of the greatest advantages of HydroFix is that it is a simple enough process for a homeowner to apply it themselves, without requiring professional equipment.

HydroFix penetrates the porous structure of the wall and forms a hydrophobic (water-repellent) layer on the inner surfaces of the pores. This layer stops the advance of water rising by capillary action. It does not impair the wall's ability to breathe; it allows the passage of water vapour but prevents liquid water from rising by capillary movement.

This guide explains every step of applying HydroFix in detail. By following the guide, you can solve your rising damp problem yourself without professional help. To get general information about rising damp, we recommend reading our article What Is Rising Damp?

Required Materials and Equipment

Before starting the application, make sure the following materials and equipment are ready. Starting the application with missing materials can force you to stop halfway and lower the quality.

Materials

• HydroFix Injection Liquid: a sufficient amount according to the length and thickness of the wall. You can calculate the exact amount by requesting a quote.
• DampStop Damp Barrier: for surface protection after HydroFix.
• Injection packers (nozzles): the plastic injection tips fitted into the holes.
• Mortar or filler: for sealing the holes.

Equipment

• Impact drill: an SDS or impact drill is required for brick and concrete walls.
• 12 mm masonry drill bit: the standard diameter for injection holes.
• Injection gun or pump: a low-pressure injection pump or cartridge gun.
• Tape measure or ruler: for measuring the hole spacings and depths.
• Spirit level: to keep the holes aligned.
• Protective goggles and gloves: against the risk of contact with chemicals.
• Dust mask: to avoid breathing in dust while drilling holes.
• Cleaning brush and broom: for cleaning up dust and residues.

Step 1: Wall Preparation

Cleaning plaster and paint: clean the loose plaster, blistering paint and dusty surfaces in the area to be injected. There is no need to remove sound plaster. Carefully lift off loose pieces with a hammer and chisel or a spatula.

Cleaning mould: if there is mould growth on the wall, clean it mechanically with a stiff brush. Mould can prevent HydroFix from penetrating the pores. In cases of heavy mould you can use an antifungal cleaner.

Checking the wall: check the general condition of the wall. If there are deep cracks, fissures or voids, these need to be repaired first. HydroFix works by spreading through the porous structure; large voids cause the liquid to be wasted.

Protecting the surroundings: protect the floor surface and nearby furniture with a plastic sheet or newspaper. Liquid may drip during injection.

Step 2: Drilling Holes

Hole Position and Height

The holes should be drilled on the interior or exterior wall surface, at a height of 10-15 cm from ground level. This height ensures the chemical barrier forms just above ground level. If application from the external wall is preferred, take care that it is above the soil level.

Hole Spacing

The distance between the holes should be 12 cm. This spacing ensures the injected liquid spreads within the wall and links the zones of effect of adjacent holes to one another. Leaving too wide a spacing causes gaps to form in the barrier.

Hole Depth

The hole depth should be about 2/3 of the wall thickness. For example, for a wall 30 cm thick the hole depth should be about 20 cm. Avoid drilling all the way through the wall; the drill bit should not come out the other side.

Hole Angle

Drill the holes horizontal or sloping slightly downwards (10-15 degrees). A slight slope ensures the injected liquid spreads better within the wall with the help of gravity. Drilling with an upward slope causes the liquid to flow back out.

Application Tips

• Set the drill to impact mode to work on brick and mortar.
• Do not apply excessive pressure while drilling; let the drill bit advance under its own weight.
• After drilling each hole, clean out dust and debris with a brush or compressed air. Dust residue prevents the injection liquid from penetrating the pores.
• Use a spirit level or a chalk line to keep the row of holes on a straight line.

Step 3: Preparing the HydroFix Mix

Ready-to-use formula: open the bottle or the cap of the drum and transfer the mix to the injection pump or gun. No dilution is required.

Concentrate formula: mix it with clean water in accordance with the mixing ratio on the product label. It is usually diluted at a 1:1 ratio (equal volumes of HydroFix and water). Mix thoroughly until the mixture becomes homogeneous.

Points to pay attention to:

• The mixing container must be clean and dry.
• Use the prepared mix within the same day; HydroFix left open can start to polymerise on contact with the air.
• The mix temperature should be between 5°C and 30°C. Do not apply in excessively hot or cold temperatures.

Step 4: The Injection Process

Injection Method

Low-pressure injection: pump the liquid into the holes using an injection pump or cartridge gun. It is important to deliver the liquid slowly and in a controlled manner. Excessive pressure can cause the liquid to seep out onto the wall surface and be wasted.

Gravity feed: in some cases, injection nozzles can be fitted into the holes so the liquid is absorbed into the wall by gravity. This method is slower but ensures a more homogeneous saturation of the pores.

Amount

The amount of HydroFix to be delivered to each hole depends on the thickness and porosity of the wall. As a general rule, the liquid should be delivered until a slight dampness appears on the wall surface around the holes. If the liquid starts to flow back out, wait a while and continue. Porous materials (brick) absorb more liquid, dense materials (concrete) less.

Order and Method

Start the injection from one end of the wall and proceed in order. After injecting each hole, move on to the next. On the first pass, deliver some liquid to all the holes, then go back to the start and do a second pass. This gives the liquid time to be absorbed on the first pass and allows more liquid to be accepted on the second pass.

Step 5: The Drying Process

After the HydroFix injection, a certain amount of time must pass for the liquid to react within the wall and for the hydrophobic barrier to form.

Drying time: a drying time of 24-48 hours is required for HydroFix to show its full effect. However, for the wall to dry out completely (for the existing moisture to evaporate) can take much longer; depending on the thickness of the wall and the existing moisture level, this period can vary between 4-12 weeks.

Points to pay attention to during the drying process:

• Do not let water come into contact with the HydroFix-treated wall for 48 hours.
• Provide good ventilation; keep windows and doors open.
• The ambient temperature should not fall below 5°C; low temperatures extend the drying time.
• Wait for drying to take place by natural means. Rather than forcing it with a fan or heater, prefer natural air circulation.

Step 6: Applying DampStop

The HydroFix injection creates the chemical barrier, but applying DampStop is the complementary step for the evaporation of the moisture remaining in the upper part of the wall and for the protection of the surface.

What DampStop does: DampStop is a damp-protection product applied to the wall surface. While it allows the moisture remaining in the area above the HydroFix barrier to evaporate in a controlled manner, it prevents new moisture from entering from outside. It also ensures the surface forms a suitable base for paint and plaster.

Application:

• Apply it to the wall area remaining above the HydroFix-treated area.
• Apply it with a roller or brush to a surface that has been cleaned and cleared of loose pieces.
• Apply the number of coats stated in the manufacturer's instructions (usually 2 coats).
• Wait the stated drying time between coats.

Step 7: Final Check

Once the application is complete, it is important to run through a final checklist to verify the quality of the work.

• Have all the holes been sealed? The injection holes should be sealed with a suitable mortar or filler.
• Has DampStop been applied evenly? Check whether there is any missed area or spot left too thin.
• Has the surrounding area been cleaned up? Clean up the dripped liquid residue on the floor and surroundings.
• Is ventilation being provided? Ensure adequate ventilation throughout the drying process.

After application, check the wall periodically for 4-6 weeks. Signs showing that the moisture level is falling (the fading of stains, the halting of salt formation) indicate that the application has been successful.

Common Mistakes

Knowing the common mistakes that lower the success rate in HydroFix application helps you avoid them.

1. Too Few Holes or Too Wide a Spacing

Increasing the hole spacing above 12 cm creates gaps in the barrier. Moisture continues to rise through these gaps and the solution fails. Reducing the number of holes in order to save material produces far more costly results in the long run.

2. Shallow Holes

A hole depth of less than 2/3 of the wall thickness causes the barrier to form in only part of the wall. Moisture can continue to rise through the inner part that the barrier does not reach.

3. Injecting into Dirty Holes

Injecting without cleaning out the dust and debris created after drilling prevents HydroFix from penetrating the pores. Be sure to clean each hole after drilling it.

4. Insufficient Amount of HydroFix

Delivering an insufficient amount of liquid to save material causes the barrier to remain weak or incomplete. Delivering a sufficient amount of liquid to each hole is critical.

5. Applying in Cold Weather

Applying below 5°C adversely affects the chemical reaction of HydroFix and can cause the barrier not to form properly. The ideal temperature range for application is 10-25°C.

6. Not Observing the Drying Time

Applying DampStop or plastering/painting before HydroFix has fully dried reduces the effectiveness of the whole application. Be patient and observe the stated drying times strictly.

To find out the amount of material required for your wall and to calculate the cost of the application, you can request a quote. For detailed information about the cost, you can read our Cost of Damp Treatment guide.